A Dose-Escalation Study Demonstrates the Safety and Tolerability of Cellobiose in Healthy Subjects.

The disaccharide and innovative ingredient cellobiose, consisting of two ß-glucose molecules linked by a ß(1→4) bond is the main component of cellulose. Cellobiose can be used within a wide variety of foodstuffs and functional foods as a low-caloric bulking agent or as a substitute for lactose. For purposes of industrial large-scale production, cellobiose is produced by an enzymatic reaction in which sucrose and glucose are converted to cellobiose and fructose. The goal of this single-arm, dose-escalation study was to evaluate the safety and tolerability of cellobiose and to determine the maximum tolerated dose of cellobiose in healthy subjects. Following a baseline period, consecutive cohorts of six subjects each consumed either single doses of 10, 15, 20 and 25 g, while 12 subjects each received multiple doses of 15 g or 20 g cellobiose (twice daily, 14 days). The main recorded parameters were stool consistency, gastrointestinal well-being (Gastrointestinal Symptom Rating Scale) and adverse events. In each highest single/multiple dosage group, some sensitive subjects experienced flatulence, borborygmus and/or transient diarrhoea. A 100% global tolerability rating makes 20 g cellobiose a tolerable dose for single use. For repeated consumption, we propose up to 15 g cellobiose twice daily (92.6% global tolerability rating). Cellobiose is a promising new ingredient with excellent tolerability.

Effect of cellobiose supplementation and dietary soluble fibre content on in vitro caecal fermentation of carbohydrate-rich substrates in rabbits.

The in vitro caecal fermentation of five substrates low in starch and protein content [d-(+)-glucose (GLU), d-cellobiose (CEL), sugar beet pectin (PEC), sugar beet pulp (SBP) and wheat straw (WS)] was investigated using soft faeces from rabbits receiving different levels of cellobiose and soluble fibre as inoculum. A total of 24 rabbits were supplemented 3 levels of cellobiose in the drinking water (0.0, 7.5, 15.0 g/l) and fed two experimental diets containing either low soluble fibre (LSF) or high soluble fibre (HSF) levels (84.0 and 130 g/kg dry matter). All substrates were subjected to a two-step pepsin/pancreatin in vitro pre-digestion, and the whole residue was used as substrate for the in vitro incubations. Gas production was measured until 144 h, and volatile fatty acid (VFA) production was determined at 24 h incubation. Experimental treatments did not affect SBP fermentation and had only a subtle influence on fermentation of WS and GLU. In contrast, cellobiose supplementation × donors' diet interactions were detected for most gas production parameters for CEL. Both the fractional gas production (k) and maximal gas production rates were linearly increased (p ≤ 0.042) and the initial delay in the onset of gas production (Lag) linearly decreased (p < 0.001) by cellobiose supplementation with the HSF inoculum, with no differences between the 7.5 and 15.0 doses. In contrast, with the LSF inoculum cellobiose supplementation only affected k values, which were quadratically increased (p = 0.043) and had maximal values for the 7.5 dose. A quadratic effect (p ≤ 0.018) of cellobiose supplementation was observed for total VFA production at 24 h when CEL and PEC were fermented, obtaining the maximal VFA production for the 7.5 dose of cellobiose. Total VFA production for CEL was greater with LSF than with HSF inoculum (20.7 vs. 12.9 mmol/l; p = 0.014), but the opposite was found for WS (3.97 vs. 6.21 mmol/l; p = 0.005). The use of LSF inoculum for CEL fermentation sharply reduced acetate (p = 0.001) and increased butyrate proportions (p ≤ 0.001) compared with the HSF inoculum. A positive relationship between total VFA caecal concentrations in rabbits receiving the same experimental treatments and in vitro values was only observed when WS was used as substrate (r = 0.90; p = 0.015; n = 6). The results suggest that experimental factors influenced the fermentative activity of caecal digesta, but the observed response differed with the incubated substrate, being the CEL the most affected.

A combination of soy isoflavones and cello-oligosaccharides changes equol/O-desmethylangolensin production ratio and attenuates bone fragility in ovariectomized mice.

We examined the cooperative effects of isoflavones and cello-oligosaccharides on daidzein metabolism and bone fragility in ovariectomized mice. Cello-oligosaccharides increased urinary equol and decreased O-desmethylangolensin. A combination of isoflavones and cello-oligosaccharides attenuated decreases in bone breaking force and stiffness caused by ovariectomy. Combination treatment with isofalvones and cello-oligosaccharides increases urinary equol/O-desmethylangolensin production ratio and prevents ovariectomy-induced abnormalities in bone strength.

Intestinal paracellular absorption is necessary to support the sugar oxidation cascade in nectarivorous bats.

We made the first measurements of the capacity for paracellular nutrient absorption in intact nectarivorous bats. Leptonycteris yerbabuenae (20 g mass) were injected with or fed inert carbohydrate probes L-rhamnose and D(+)-cellobiose, which are absorbed exclusively by the paracellular route, and 3-O-methyl-D-glucose (3OMD-glucose), which is absorbed both paracellularly and transcellularly. Using a standard pharmacokinetic technique, we collected blood samples for 2 h after probe administration. As predicted, fractional absorption (f) of paracellular probes declined with increasing Mr in the order of rhamnose (f=0.71)>cellobiose (f=0.23). Absorption of 3OMD-glucose was complete (f=0.85; not different from unity). Integrating our data with those for glucose absorption and oxidation in another nectarivorous bat, we conclude that passive paracellular absorption of glucose is extensive in nectarivorous bat species, as in other bats and small birds, and necessary to support high glucose fluxes hypothesized for the sugar oxidation cascade.

Paracellular absorption in laboratory mice: Molecule size-dependent but low capacity.

Water-soluble nutrients are absorbed by the small intestine via transcellular and paracellular processes. The capacity for paracellular absorption seems lower in nonfliers than in fliers, although that conclusion rests largely on a comparison of relatively larger nonflying mammals (>155g) and relatively smaller flying birds (<155g). We report on paracellular absorption in laboratory mice, the smallest nonflying mammal species studied to date. Using a standard pharmacokinetic technique, we measured the extent of absorption (fractional absorption=f) of inert carbohydrate probes: L-arabinose (M(r)=150.13Da) and cellobiose (342.3) that are absorbed exclusively by the paracellular route, and 3-O-methyl D-glucose (3OMD-glucose) (M(r)=194) absorbed both paracellularly and transcellularly. f was measured accurately in urine collection trials of 5-10h duration. Absorption of 3OMD-glucose by mice was essentially complete (f=0.95±0.07) and much higher than that for L-arabinose (f=0.21±0.02), indicating that in mice, like other nonflying mammals, >80% of glucose is absorbed by mediated process(es) rather than the passive, paracellular route. As in all other vertebrates, absorption of cellobiose (f=0.13±0.02) was even lower than that for L-arabinose, suggesting an equivalent molecular size cut-off for flying and nonflying animals and thus a comparable effective TJ aperture. An important ecological implication is that smaller water-soluble plant secondary metabolites that have been shown to be absorbed by the paracellular path in cell culture, such as phenolics and alkaloids, might be absorbed in substantial amounts by bats and small birds relative to nonflying mammals such as mice.

Effect of Lactobacillus rhamnosus KY-3 and cellobiose as synbiotics on lipid metabolism in rats.

Lactobacillus rhamnosus KY-3 is a fermentative bacterium that is used for the industrial production of L-lactic acid. We have examined the effect of L. rhamnosus KY-3 and cellobiose as synbiotics on lipid metabolism in rats. Rats were fed on a 20% casein diet (C) supplemented with either 1.7% L. rhamnosus KY-3 (KY-3), 10% cellobiose (CEB), or 1.7% L. rhamnosus KY-3 and 10% cellobiose (KY-3+CEB) for 13 d. The concentrations of serum total lipids, triacylglycerol, total cholesterol, and phospholipids were significantly reduced in rats fed a KY-3+CEB diet in comparison to those on the C, KY-3 and CEB diets. There was an increase in the weight of cecal contents and a significant increase in the amount of cecal short-chain fatty acids (SCFA). The dry weight of excretion increased additively upon the simultaneous administration of L. rhamnosus KY-3 and cellobiose (KY-3 + CEB). The amount of excreted fecal bile acids did not differ among the groups in this study. These findings support the hypothesis that the promotion of cecal fermentation can lower the level of serum lipids. These results suggest that simultaneous administration of L. rhamnosus KY-3 and cellobiose as synbiotics has a beneficial effect on lipid metabolism.

Intestinal permeability assessment before and after ileal pouch-anal anastomosis.

AIM: Intestinal permeability is considered an index of anatomic and functional integrity of the small intestine mucosa. Altered intestinal permeability has been suggested to be a possible cause of pouchitis. Aim of this paper was to assess variations in intestinal permeability during the first year of a pouch reconstruction. METHODS: Intestinal permeability (IP) was investigated in 8 ulcerative colitis patients before and after total proctocolectomy, with ileal pouch-anal anastomosis (IPAA), by means of the cellobiose/mannitol test. To each patient a basal test (before surgery) and 3 more tests during a 1 year follow-up were administered. RESULTS: Individual data were altered despite clinical findings in 9 of 30 IP measured values. An overall pattern of unaffected permeability was however shown and none of our patients, during the first year follow-up, has developed pouchitis. CONCLUSIONS: Six of the 8 investigated patients presented at least 1 altered IP value. A longer follow-up aimed to further investigate patients beyond the first year after IPAA confection as to the occurrence of pouchitis and its possible correlation with a previous permeability alteration of the pouch mucosa is in progress.

Pitfalls in gastrointestinal permeability measurement in ICU patients with multiple organ failure using differential sugar absorption.

OBJECTIVE: To assess whether gastrointestinal permeability (GIP) at intensive care unit (ICU) admission, measured by differential sugar absorption, is related to severity of disease and multiple organ failure (MOF). Post hoc, to analyse the relation between the urinary sugar recovery and renal function. DESIGN: Prospective observational cohort study. SETTING: Eighteen-bed general ICU of a teaching hospital. PATIENTS: Sixty-four ventilated patients admitted with MOF. INTERVENTIONS: GIP was assessed within 24 h using cellobiose (C), sucrose (S) and mannitol (M) absorption. MEASUREMENTS AND RESULTS: Severity of disease: APACHE II and III, SAPS II and MPM II systems. Organ failure: SOFA, MODS and Goris score. The median urinary recovery of C was 0.147% (range 0.004-2.145%), of S 0.249% (0.001-3.656%) and of M 10.7% (0.6-270%). In 16 patients, M recovery was over 100% of the oral dose. They received red blood cell transfusion (RBC). In the non-transfused, the median cellobiose/mannitol (CM) ratio was 0.015 (0.0004-0.550). CM ratio was not related to severity of disease and inversely related to the SOFA score ( r=-0.30, p=0.04). Post hoc regression analysis showed that recoveries of C, S and M were positively related to urinary volume. Recoveries of C and S, but not of M, were positively related to creatinine clearance. The CM ratio corrected for diuresis, but was inversely related to creatinine clearance. CONCLUSIONS: Differential C, S and M absorption testing is unreliable after RBC transfusion, since bank blood contains mannitol. The excretion of C and S, but not of M, is limited by renal dysfunction. Differential sugar absorption is not reliable to test GIP in MOF patients, since non-permeability related factors act as confounders.

Effect of dilution rate, cellobiose and ammonium availabilities on Clostridium cellulolyticum sporulation.

The nutritional and physiological factors affecting sporulation of Clostridium cellulolyticum were studied using steady-state continuous cultures grown in both complex and synthetic media. Under cellobiose limitation, the probability that cells will sporulate appears to be directly related to the growth rate. In complex medium, the highest percentage of sporulation was 20% at a dilution rate of 0.015 h-1 whereas in synthetic medium it was 10% at 0.035 h-1. In both media, when the dilution rate was either higher or lower the percentage of sporulation decreased by between 2% and 4%. At low dilution rates, endospore formation was repressed under cellobiose-sufficient concentrations, suggesting catabolite repression by cellobiose. Furthermore, the concentration of ammonium was important in determining the percentage of sporulation, as ammonium limitation induced extensive sporulation at low growth rates even in an excess of cellobiose. The sporulation process is not triggered when cells are cellobiose-exhausted both in complex and synthetic media. These data suggest that, in C. cellulolyticum, an exogenous supply of carbon is required throughout the sporulation process. In the experimental conditions used in this work, no relationship between glycogen accumulation or glycogen mobilization and endospore formation was detected in C. cellulolyticum.

Fate of intravenously injected aminated beta(1----3) polyglucose derivatized with 125I-tyraminyl cellobiose.

Aminated beta(1----3)glucan (polyglucose, AG), a potent soluble immunomodulator, was radio-iodinated and traced after intravenous administration to rats. Since the glucose polymer cannot be 125I-labelled directly by conventional methods, the polysaccharide had to be substituted with an adduct which binds the radiolabel. To this end, tyraminyl cellobiose (TC) was coupled to amino groups of AG by means of cyanuric chloride. This procedure resulted in a degree of substitution corresponding to 3.6% (or 1 molecule of tyraminyl cellobiose being incorporated per 28 molecules of glucose). AG substituted with TC (TC-AG) could be labelled with 125I by conventional procedures. After intravenous administration of 125I-TC-AG the serum concentration dropped about 50% from 1 min to about 15 min after injection, while a further drop from 50% to about 25% was observed during the next 15-60 min. The finding that 60 min after injection most of the radioactivity was recovered in the kidneys and urine, together with the results from gel chromatography showing that the low Mw fraction of the injected material disappeared first from the circulation, suggests that the initial rapid phase of elimination is due mainly to glomerular filtration. The molecules that are too large for kidney excretion are taken up mainly by the liver (about 10% of injected dose) at a slower speed. This notion was supported by the finding that a preparation of high Mw glucan obtained by gel chromatography survived for a long period in the circulation, and was eliminated mainly by accumulation in liver, whereas a preparation of low Mw glucan was rapidly eliminated by glomerular filtration. Several days after injection the liver contained nearly 90% of the recovered radioactivity, whereas the kidneys and other organs contained only insignificant amounts. This indicates that radioactivity associated with the kidneys after 60 min reflects glomerular filtration, whereas radioactivity in liver results from uptake leading to lysosomal accumulation. Isolation of liver cells after injection disclosed that the radioactivity per cell was the same in Kupffer cells (KC) and liver endothelial cells (LEC), whereas the uptake per parenchymal cell (PC) was about 30% of the uptake per KC and LEC. It could be calculated that in the intact liver, the population of PC was responsible for 50% of the uptake, whereas the populations of LEC and KC contained 35% and 15%, respectively, of the total liver radioactivity. These findings raise the question whether not only KC, but also LEC and PC may be mediators of the immune responses caused by beta(1----3) polyglucose.

Utilization of intravenously administered beta-cellobiose and maltose by young pigs.

Intravenous solutions of glucose oligosaccharides are potential sources of carbohydrate-derived energy for patients requiring intravenous feeding. Relatively little is known about utilization of glucose oligosaccharides linked by beta-glucosidic bonds. We compared the utilization of maltose (alpha-D-glucosyl-1,4-D-glucose) and beta-cellobiose (beta-D-glucosyl-1,4-D-glucose) when administered intravenously (19 g per day) to young pigs for a 5-day period. Animals infused with maltose excreted 15% of the infused disaccharide over the 5-day infusion period. No evidence of maltose accumulation was noted in plasma, and kidney morphology was normal. Animals infused with beta-cellobiose excreted 95% of the infused disaccharide in the urine. The mean (+/- SD) plasma total glucose concentration increased significantly over base-line values of 114 +/- 39 mg/dl to a value of 180 +/- 28 mg/dl during cellobiose infusion, indicating accumulation of cellobiose in body water. Kidney morphology in cellobiose-infused animals was normal. Intravenously infused beta-cellobiose is poorly utilized by the pig when compared with the utilization of its alpha-1,4 linked isomer, maltose.